The invention relates to a method for controlling a welding unit and a current source, as well as a control arrangement.
Methods for controlling welding units and current sources and a device required for this purpose are known, which enable different welding parameters, such as a welding current, an additional material, a welding method, for example, etc., to be set from an input and/or output device, so that the control device can control the individual components of the welding unit accordingly on the basis of the pre-set welding parameters enabling a user to perform a corresponding welding process.
From WO 97/10919 A, in particular EP 0 865 858 A1, an automatic welding input device is known, which is connected to a robot welding system, in particular a robot and a welding unit. This being the case, a user can set the most varied of parameters by means of the welding input device, in particular via a computer screen, after which the computer will devise a welding process and the corresponding values are forwarded to the robot welding system. The user can edit the shape or form of the weld joint and the bead, which are graphically presented, from the welding input device, whereupon the other parameters needed to produce this weld joint are adjusted and these are forwarded to the robot welding system.
Although using this type of graphical feature to determine the form of a weld seam does make it easier to produce a simple weld seam or configure the welding unit to produce a simple form of weld seam, a system of this type is not without major disadvantages:
1. an additional input unit has to be connected to the welding unit or robot welding unit, which can lead to cabling errors;
2. the occurrence of faults is significantly increased due to additional line connections to external components, particularly because of the high currents used in welding technology, so that it is not usually possible to operate systems of this type over long periods without faults occurring, which means that these robot welding systems always have to be monitored or a high degree of complex screening is necessary;
3. input devices of this type can usually only be used with a specific type of welding unit, which means that different input devices are needed for different welding units or if one input unit is used for several types of welding unit it will not be possible to use all tool functions, in particular parameters, for the different welding units;
4. a significant disadvantage in particular is the fact that only certain welding parameters can be set or used to produce a simple weld seam and optimum welding quality can therefore not be produced.
The underlying objective of this invention is to propose a method of controlling a welding unit and a current source as well as a control device, whereby welding parameters can be easily entered or edited to enable a welding process to be configured and performed accordingly.
According to one aspect of the invention, this object is achieved by a method which comprises the step of setting and storing by an input or output device, before the start of a welding process, various welding parameters selected from the group of the welding current, the welding wire diameter, the welding speed and a surface area or cross section of a welding seam as well as a measurement of the welding seam with various parameters selected from the group of the seam thickness, the seam width and the side length of the welding seam, the seam thickness being displayed by a light-emitting diode and a symbol on a front plate of the input or output device and being called up for the measurement of the welding seam. The stored parameters are retrieved and displayed for the formation of desired parameters of the welding seam for the welding process, the stored parameters are entered in a control device, and the welding unit comprising the current source is controlled by the control device containing the stored parameters while continuously adjusting the stored parameters to the prevailing welding speed or the welding speed to the stored parameters to produce the pre-set welding seam.
The advantage of this arrangement is that by setting the surface area or cross section of the weld seam, in particular a fillet weld, the user will be assisted in finding the welding parameters, which brings a considerable saving in the time needed to search for individual welding parameters since the user will no longer need to carry out any or will need to perform only a few test welds in order to produce a corresponding weld seam, in particular a fillet weld. Another advantage resides in the fact that in order to form a corresponding weld seam, in particular a fillet weld, personal welding parameters to which the user has become accustomed over the years, as would be the case with the welding speed for example, can be stored in the control device and in the welding unit and applied for the purposes of computing the weld seam or the individual welding parameters to produce a corresponding, predetermined weld seam to user-defined welding parameters.
Advantageously, because the individual welding parameters needed to produce a specific predetermined weld seam are computed by the welding unit or the control device, the welding seam can be produced by unskilled personnel without having to perform laborious test welds.
The invention also relates to a control arrangement for a welding unit comprising a current source to produce a pre-set welding seam, which comprises a control device, an input or output device arranged on the welding unit and connected to the control device for entering therein various welding parameters selected from the group of the welding current, the welding wire diameter, the welding speed and a surface area or cross section of a welding seam as well as a measurement of the welding seam thickness, a memory device for storing desired welding parameters which are settable and changeable by the input or output device, a power component, a display element comprised of a light-emitting diode and a symbol on a front plate of the input or output device for calling up the measurement of the welding seam thickness for entering the measurement of the welding seam in the control device, and a welding speed measuring device associated with the welding unit for detecting the welding speed.
The advantage of this arrangement is that an accurate welding process can be computed by the control device for a specific weld seam to avoid faulty welding.